The first step in the manufacture of adipic acid and caprolactam is oxidizing cyclohexane to produce a mixture containing unreacted cyclohexane, cyclohexanone, cyclohexanol and cyclohexylhydroperoxide (CHHP), and treating the mixture with aqueous caustic to decompose the CHHP into more cyclohexanone and cyclohexanol. The treatment results in a biphasic mixture: an organic phase, containing primarily cyclohexane, cyclohexanone and cyclohexanol, and an aqueous phase containing primarily water, organic salts and caustic. However, inevitably some caustic tends to remain in the organic phase in the form of dispersed droplets. Isolation of the cyclohexanone and cyclohexanol is accomplished typically by fractional distillation, in which the cyclohexanone is exposed to heat. In commercial operations, fractional distillation is conducted in metallic stills which frequently are made from metals which are susceptible to corrosion when contacted by acidic media. Even a small amount of caustic present during this fractional distillation step can catalyze the oligomerization of some of the cyclohexanone, resulting in yield loss. Moreover if the cyclohexanone/cyclohexanol mixture is converted to adipic acid, the presence of cyclohexanone oligomers can cause fouling of equipment and contamination of adipic acid. It would be desirable to have a way of limiting the extent of cyclohexanone oligomerization in the processes described above.